Generally, continuous carbon fiber reinforced thermoplastics are formed by continuously embedding a reinforcing fiber such as a glass fiber or a carbon fiber in a plastic having a relatively low degree of mechanical strength. Such continuous carbon fiber reinforced thermoplastics have very high degrees of mechanical strength, rigidity, and impact resistance, as compared to short fiber reinforced thermoplastics (SFTs) having reinforcing fibers contained therein having a fiber length of 1 mm or shorter or long fiber reinforced thermoplastics (LFTs) having a fiber length of about 5 mm to about 50 mm, such as glass mat-reinforced thermoplastics (GMTs).
In addition, since continuous carbon fiber reinforced thermoplastics have high degrees of flexibility, continuous carbon fiber reinforced thermoplastics can be unidirectionally or bidirectionally woven, and woven continuous carbon fiber reinforced thermoplastic materials can be used in many products requiring various mechanical properties.
Generally, continuous carbon fiber reinforced thermoplastics may be manufactured by methods such as a pultrusion method or a commingling or hot pressing method.
In a pultrusion method, a continuous fiber tow is impregnated with a plastic resin by spreading the continuous fiber tow out widely and passing the widely spread continuous fiber tow through a bath or die containing a liquid or melted resin. Although the degree of impregnation may be increased by optimizing process conditions of a pultrusion process, it is difficult to control the amount of a reinforcing fiber such as a continuous fiber and the amount of a plastic resin being mixed, and continuous fibers processed by the pultrusion method may not be easily woven due to having a low degree of flexibility.
Furthermore, if a heating method of the related art is used, films may be melted from surfaces thereof, and thus the films may be easily bent on the melted surfaces.
Therefore, it is necessary to provide a method for manufacturing a continuous carbon fiber reinforced thermoplastic prepreg without the above-mentioned problems, to allow the method to be usefully used in related fields.